Continuous passive motion applied to an injured limb is a common method of rehabilitative treatment. The devices capable of providing such treatment are typically designed to repetitiously move the limb through a range of positions as medically prescribed. Such machine-applied continuous passive motion promotes the general health and well-being of patients and reduces the time required for rehabilitation.
While devices of the type described are in most cases capable of providing the required rehabilitative therapy, they often involve complex structures that depend upon electrically-driven actuators. Furthermore, the devices usually depend upon mechanical components such as power screws, and the like; components which necessitate relatively close tolerances.
In addition, CPM devices that are dependent upon mechanical interrelationships undergo continual physical stressing that normally results in a high rate of wear-and-tear, and as a consequence, a need for specialized repairs. In addition to their relative complexity and expensive construction, such mechanically driven devices are frequently heavy and therefore cumbersome to transport. Furthermore, they are often associated with operating sounds of the type typically attendant to mechanically-driven devices, sounds that become increasingly objectionable to patients as a consequence of their repetitive nature.
In view of the preceding, it is a first aspect of this invention to provide a continuous passive motion device that does not rely on motor driven mechanical linkages to provide desired physical therapy routines.
A second aspect of this invention is to provide a passive motion device that is less costly to build and to maintain, and that operates relatively quietly.
Another aspect of this invention is to provide a CPM device of relatively simple construction that contains no moving mechanical parts in the drive portion thereof, and one which can therefore be manufactured with less demanding tolerances.
A further aspect of this invention is to provide a CPM device whose simplicity of construction lends itself to modular construction, and therefore to rapid, inexpensive repair, for example, by modular replacements.
An additional aspect of this invention is to provide a continuous passive motion device that is actuated by the application of fluid (either gas or liquid, and preferably air) pressure to the device.
Yet another aspect of this invention is to provide a pneumatic fluid force-generating device, capable of generating an actuating force through the repeated inflation and deflation of adjacent bladders, one part of each of which is anchored at a common hinge point.
Still an additional aspect of this invention is to provide a CPM device having means for controlling the angular positioning between two members which are pivotal with relation to each other, through the interruption of a light beam passing between a light-emitting diode and a phototransistor which forms a part of the device.